Apparatus for removing foreign particles from a lithographic press

ABSTRACT

A pickup blade of plastic material is slidably mounted for longitudinal movement in a block which is pivotally mounted to a lithographic press frame. An actuating means is operable from a position where an operator can view the finished printed product coming from the press. The actuating means pivots the block to bring the pickup blade into contact with an entire longitudinal edge of a lithographic plate cylinder to pick up foreign particles or to dislodge them sufficiently so that they will be picked up by other existing rollers and removed from the printing surface. The pickup blade can be slid longitudinally off the block to position clear of the press and can then be replaced with a new blade or cleaned and returned to position in the block. This can be done without stopping the press and without inserting the operator&#39;&#39;s fingers into dangerous positions during operation of the press. In order to obtain rigidity of the support of the blade across the entire longitudinal edge of the plate cylinder, the blade and block can be mounted on a relatively thick walled cylindrical tube which is mounted to the press frame to rotate about its central longitudinal axis.

United States Patent [191 Grindeland APPARATUS FOR REMOVING FOREIGNPARTICLES FROM A LITHOGRAPHIC PRESS [76] Inventor: Gordon L. Grindeland,7526 Harriet Ave., Minneapolis, Minn. 55423 [22] Filed: 3 July 26, 197221 Appl. No.: 275,281

Related US. Application Data [631' Continuation-impart of Ser. No.167,920, Aug. 2,

1971, abandoned.

[52] US. Cl l0l/425, 15/236 R, 15/256.5l,

. 101/169, 118/104 [51] Int. Cl. B4lf 35/00, B41f 41/00 [58] Field ofSearch 101/423-425,

[4 Ju1y9,1974

Primary Examiner-Clyde 1. Coughenour Attorney, Agent, or Firm-Dorsey,Marquart, Windhorst, West & Halladay 1 ABS IRACT A pickup blade ofplastic material is slidably mounted for longitudinal movement in ablock which is pivotally mounted to a lithographic press frame. Anactuating means is operable from a position where an operator can viewthe finished printed product coming from the press. The actuating meanspivots the block to 1 bring the pickup blade into contact with an entirelongitudinal edge of a lithographic plate cylinder to pick up foreignparticles or to dislodge them sufficiently so that they will be pickedup by other existing rollers and removed from the printing surface. Thepickup blade can be slid longitudinally off the block to position clearof the press and can then be replaced with a new blade or cleaned andreturned to position in the block. This can be done without stopping thepress and without inserting the operators fingers into dangerouspositions during operation of the press. In order to obtain rigidity ofthe support of the blade across the entire longitudinal edge of theplate cylinder, the blade and block can be mounted on a relatively thickwalled cylindrical tube which is mounted to the press frame to rotateabout its central longitudinal axis.

6 Claims, 7 Drawing Figures [56] References Cited UNITED STATES PATENTS1,509,612 9/1924 Ruckriegec 15/256. 5l 1,993,352 3/1935 Schwartzl5/256.51 2,188,114 l/l940 Hubbard 15/236 R X 2,534,320 12/1950 Taylor118/126 3,026,796 3/1962 Crawford 101/157 3,144,826 8/1964 Lang etal.... 101/425 3,327,341 6/1967 Kuehn 15/256.51 3,660,863 5/1972 Gerbasil5/256.51

ii! uiufji' PATENTED JUL 91574 smurf;

I F iii. :1. will fi v.n mm 2 1N VENTOR. 420/200 4, Gran/0544410 BY M IPATENTED L 9 I 74 SHEET 2 0f 3 PATENTEU- 9l974 APPARATUS FOR REMOVINGFOREIGN PARTICLES FROM A LITHOGRAPHIC PREss BACKGROUND OF THE INVENTIONThis invention is a continuation-in-part of my application, Ser. No.167,920, filed Aug. 2, 1971 for APPA- RATUS FOR REMOVING FOREIGNPARTICLES FROM A LITI-IOGRAPI-IIC PRESS, now abandoned.

DESCRIPTION OF THE PRIOR ART The removal of foreign particles, commonlycalled hickies," from the lithographic plate of a lithographic press haslong been a problem.-The problem is twofold. First, the particles mustbe removed to achieve perfectly, printed products. Second, the means andmethod for removing the particles should not entail even an opportunityfor the operator to reach into dangerous areas whilethe press'isrunning. This problem has persisted in spite of the issuance of patentsdesigned to alleviate it. For example, it has been suggested topivotally mount a relatively narrow scraper blade on a shaft in parallelspaced relationship from the surface of the plate cylinder, to providestructure which allows longitudinal movement of the blade along theshaft and to provide for a handle so that the plate can be mechanicallybrought into contact with the plate cylinder at various places along thecylinder to attempt to remove deleterious materials. See U.S. Pat. No.3,144,826. Unfortunately, this calls for an operator to observe thepresence of a'blemish on the finished work .high above the output end ofthe press-and to have him or another operator move the scraper bladelongitudinally into position in'radial alignment with the blemish on theplate cylinder and then to manually activate the device to cause thescraper blade to come in contact with the plate cylinder. Thislongitudinal movement to obtain radial alignment with the hickey and thenecessity to mechanically pivot the scraper blade into the platecylinder is dangerous to the operator and has presented such otherdifficulties that the structure has not been widely accepted. I

A further difficulty with the short scraper blad structure is that thewearing or temporary effect which the scraper blade has on the finishedprinting due to its contact with only part of the lithographic platetends to cause bands of non-uniform printing to result on the finishedproduct.

Other uses of scrapers on limited areas of lithographic plates have beenproposed. For example, U.S. Pat. No. 3, 108,539 utilizes scrapers toremove ink from first and second feed cylinders to prevent migration ofone color of ink into the area of another color of ink. Here the effectis clearly to operate on narrow bands of rotating cylinders only, whichis just exactly the opposite effect needed to successfully removehickies from the entire surface of a plate cylinder during operation ofa lithographic press.

It has been. proposed toposition a relatively narrow wiper-memberagainst the plate cylinder and to cause this member to move back andforth across the face of the plate cylinder constantly during'operationof the press to attempt to disturb hickies tothe end thatthey can bepicked up later in their movement with the plate cylinder by the inkingrolls or other rolls and thus be removed from the plate cylindern SeeU.S. Pat. No. 3,252,416. This structure has also proved unsatisfactoryand has not been generally adopted since the patent issued. This patent,however, provides an excellent discussion of the danger and problem ofremoving hickies in column 1 and in column 2 to line 63.

As pointedout in us. Pat. No. 3,252,416, referred to above, rotatingleather rollers extend the full length of the plate cylinder have beenproposed, but these rollers and other similar rollers tend to quicklyfill with hickies and the time lost in shut-down for the replacing ofthe rollers is considerable.

Positively driven rollers rotating at speeds different from that of theplate cylinder in which they are in contact have also been suggested.See U.S. Pat. No. 3,467,008. This method calls for disturbing the hickeyto cause it to be picked up by the positively rotating roller to becarried into the other rollers of the fluid supply system where therollers can be removed from the collection point in a single operationafter a given printing run of the press has been completed. Column 3 ofU.S. Pat. No. 3,467,008, lines -71 through 73. It is to be noted that nomeans is provided for cleaning the accumulated hickies from the machineduring operation of the press. A v i In the standard printing art,various devices have been suggested for scraping or cleaning one or moredrums by positioning scraper blades across the entire surface of suchdrums. See US. Pat. Nos. 3,194,156; 3,468,248; 3,327,341; 3,026,796; and3,593,663. These patents have to do with bringing blades in contact withrollers generally in the printing art, but are believed to be notpertinent to the problem of disturbing the surface of a lithographicplate which is actually performing the offset print ou'tprocess in sucha manner as to pick up or at least to loosen hickies which are presentthereon. In general, these patents are no I more pertinent than wouldbe. the prior art structure of an old-fashioned Steamroller to scrapethe tar and road surface particles from the roller in the process ofcompacting a roadway.

Use of a pad across the entire surface of theoffset cylinder has beensuggested, and it has been suggested that moisture be added to this padto prevent a change of condition in the offset plate, either drying itout or leaving it-too wet. See U.S. Pat. No. 3,094,068. The problem of apad filling up with hickies during a run and thereby necessitating theshutdown of the press during the runs, however, is a serious one and hasprevented this structure from being widely accepted.

In order to provide uniformity of operation acrossthe v entire surfaceof the plate cylinder, it is essential that the axis upon which thepickup blade rotates is exactly parallel to the outer surfaceof thelithographic plate as supported on the plate cylinder. Likewise, it isimportant that the exactly correct relationship between the pickup bladeand the lithographic plate, supported on its cylinder, be establishedand maintained in spite of the wearing of the pickup blade, and anychanges in the size of replacement pickup blades.

SUMMARY OF THE INVENTION a blade block which is pivotally mounted topermanent frame portions of the lithographic press to move between afirst position in which the edged pickup blade is in contact with theplate cylinder to disturb hickies and remove them therefrom and to asecond position in which the edged blade will be in clearing relation tothe plate cylinder. In many installations, the slot and blade will belongitudinally or transversely in clearing relation to the frame of thepress. This will allow the blade to be removed from the block andreplaced or cleaned to remove hickies therefrom and returned to the drumwithout disassembly of any other part of the press or the apparatus forremoving hickies. The blade can also be cleaned in place with asolvent-coated cloth when the press is stopped.

A remotely operated power linkage between the frame of the printingpress and the block is controlled from a location where an operator canobserve the quality of the printing leaving the press, and is operativeto move the blade and block between the aforementioned first and secondpositions as determined by the operator upon observation of the finishedwork product leaving the press.

In order to insure that there will be no deflection of the edge of thepickup blade out of exact parallel alignment with a longitudinal edge ofthe lithographic plate on its rotating plate cylinder, the block-inwhich the pickup blade is mounted can be integrally attached to orconstituted as a part of a relatively thick walled rigid cylinder whichis mounted on bearings at either end of the plate cylinder on the pressframe. In order to achieve accurate adjustment of the relationship ofthe pickup blade to the lithographic plate on the cylinder, thesebearings can be mounted for independent movement toward and away fromthe rotating plate cylinder.

In the drawings:

FIG. 1 is an elevational view of a portion of a lithographic printingpress showing a hickey" pickup blade of a first form of the presentinvention in contact with a portion of a lithographic plate on a platecylinder of the press; 1

FIG. 2 is a fragmentary rear elevational view of a portion of the pressof FIG. I further showing the relationship of the pickup blade and ablock with respect to the lithographic printing plate and platecylinder",

FIG. 3 is an enlarged fragmentary vertical sectional view taken on theline 33 in FIG. 2;

FIG. 4 is a further enlarged transverse sectional view of the pickupblade and block;

FIG. 5 is a fragmentary elevational view of a portion of a lithographicprinting press showing a hickie" pickup blade of a second fonn of thepresent invention in contact with a portion of a lithographic plate on aplate cylinder of the press, and showing the supporting and operatingapparatus and mechanism for that blade;

FIG. 6 is a sectional view taken on the line 6-6 in FIG. 5; and

FIG. 7 is a vertical sectional view taken on the line 7-7 in FIG. 6.

DESCRIPTION OF PREFERRED EMBODIMENTS:

Offset lithographic presses are widely utilized in the printing fieldthroughout the world and details of construction of such presses arewell known. As disclosed in US. Pat. No. 3,467,008, for example,lithographic presses can include plate, blanket, impression and transfercylinders of essentially the same size and rotating at the same speedrelative to each other from a common drive source. Other rollersconstitute dampening and inking supply systems. For example, as shown inthat patent, a plate cylinder 2 is contacted by water applying rollers21 and 22, inking rollers 42 and 43, and secondary inking rollers 48 and49. Similar rollers will, of course, be present on the lithographicpresses incorporating the invention disclosed herein, but have beenomitted from the drawings for the sake of clarity.

As seen in FIGS. 1 through 4, in a first form of the invention, alithographic press 10 includes a press frame 12 having upright sideframe members 14 and R6 tied together by transverse tie rods 18, one ofwhich is shown. A plate cylinder 20 is rotatably mounted in the sideframe members as at 22, and has a lithographic plate 24 affixed theretoin any usual or preferred manner. During operation of the press, theplate cylinder will be rotated in a counter-clockwise direction, as seenby the arrow 26 in FIG. 3.

As shown, a pair of generally upright support arms 28,28 are fixedlyclamped on the transverse tie rod 18 as at 30, and a pickup blademounting block 32 is pivotally supported between the arms 28,28 throughthe instrumentality of pivot pins or bearings 34 which extend inwardlyfrom arms 28,28 and which can be adjusted to achieve precise positioningof the block 32. Block ears 36 extend downwardly from the block and eachis pivotally connected to an actuating arm or piston rod 38 whichextends upwardly from an air-operated piston-cylinder motor 40 likewisefixedly mounted with respect to the tie rod 18 as at 42.

An edged pickup blade 44, made of polyethlene, polytetrafluoroethylene(TFE), neoprene or some other suitable material, is mounted forlongitudinal movement with respect to the blade block 32 in direction inalignment with the axis of the plate cylinder, and is provided with aworking edge 54. The blade 44 is also provided with a T-bar extension 46which is received into a Tslot 48 provided in the blade mounting block32.

It is to be noted that the side frame members 14 and 16 are providedwith outwardly extending brackets 50,50 to support other equipment onthe press, but that these brackets are each provided with an opening 52therethrough. This allows access to either end of the pickup blade 44,so that when the blade is situated in spaced relationship to thelithographic plate 24, it can be pushed from one end to slide withrespect to the block 32 and extend out through the other endsufficiently so that it can safely be grasped and pulled from the blockwhen it is necessary or desirable to clean it or to replace it becauseit has become worn on its edge 54. By using a push rod from one end tomove the blade far enough beyond the side frame member at the other end,removal and replacement of the blade can be accomplished. Thus there isno chance of accident and injury to the operator.

In operation, air lines 56,56 from a source of pressure (not shown)extend to and through a control switch 58 to each cylinder 40 as shownschematically in FIG. 3. This switch is located in actual practicewithin easy reach of an operator positioned to watch the finished workcome off of the press. When the operator detects thepresence of foreignparticles on the lithographic plate 24, as evidenced by imperfections inthe finished work, he activates the control switch to cause the aircylinder 40, acting through control arm 38 on block ears 36, to rotatethe block about the pivot pins or bearings 34 to cause the working edge54 of pickup blade 44 to come into contact with the lithographic plate24, to pick up the foreign particles on the plate, or to dislodge themin such a manner that they will be picked up by subsequent rollers andcarried from roller to roller away from the plate cylinder in a mannerwell known in theart. It is helpful that the blade used has at leastsome slight electrostatic tendencies so that the particles will tend toadhere thereto. Good results can be obtained when the pickup blade'ofthe invention contacts the lithographic plate either just before or justafter the plate is contacted by the dampening rollers.

When the. operator has accomplished his result in clearing the plate, hereleases the control switch 58, and the piston rod arms 38 relax underan internal bias to cause the pickup blade 44 and mounting block 32 totake the position as seen in dotted lines in FIG. 3. The block ismounted to then be in clearing alignment with the frame so the blade canbe removed from the block in the manner aforesaid.

Good results can be obtained when this angle defined by the planesintersecting to form working edge 54 is as great as 90 as long as theangle between the blade vwall surface opposite the direction towardwhich the plate cylinder is rotating and a plane tangent to thecylinder, extending away from the direction of cylinder rotation andincluding the working edge of the blade is 90 or less.

Referring now to the second form of the invention as seen in FIGS.through 7, a lithographic press 110 includes a press frame 112 havingparallel spaced apart upright side frame members 114 and 116. These sideframe members are tied together by transverse tie rods 118, one of whichis shown. A plate cylinder 120 is rotatably mounted in the side framemembers and has a lithographic plate 124 affixed thereto in any usual orpreferred manner. During operation of the press, the plate cylinder willberotated in a counter-clockwise direction, as seen by arrow 126 in FIG.5.

As shown, a pickup blade assembly -131'includes pair of mounting arms128 which are fixedly clamped on the transverse tie rod 118 as at 130.In order to insure complete rigidity and accurate positioning. of theparts, a pickup blade 144 is mounted in a T-slot 148 provided in apickup blade mounting block 132 which in turn is integrally connected asat 135 to a rigid thick walled cylindrical tube 137. Extending fromopposite ends of the tube 137 are stub shafts 139,139. Collars 141,141are also carried on these stub shafts. The tube 137 and collars 141,141are keyed to the stub shafts 139,139 as at 143.

As shown, the outer races of ball bearings 145,145 are fixedly mountedin the outer ends of collars 141,141 while the inner races are fixedlymounted on mounting studs 147,147, each of which consist of threeaxially aligned cylindrical portions, the middle portion being ofgreater diameter than the two end portions.

Mounting arms 128 are each provided with a mounting stu'd receiving slot149. A threaded positioning rod 151, controlled by a knurled hand knob153, impinges on the outer end of mounting stud 147 when it is.situatedin slot 149 to positively set the relative position of the mountingstuds, and hence the entire pickup assem- FIG. 7.

v 6 bly and including particularly the mounting blade, with I respect tothe outer periphery of the plate cylinder and of the lithographic plate124.

At one end of the pickup blade assembly 131, an .air operatedpiston-cylinder motor 140 is pivotally mounted on a bracket 155 whichitself is integrally mounted on the bottom side of one of the mountingarms 128. The collar 141 at that end of the pickup blade assembly has anintegral operating finger 157 extending outwardly therefrom, and thepiston of the motor 140 is pivotally mounted thereto, as best seen in Inoperation, an air line 156 from a source of pressure (not shown) extendsto and through a control switch 158'to the motor 140, as shownschematically in FIG. 6'. As in the case with the first form of theinvention, this switch is located within easy reach of an operator whois positioned to watch the finished work come off of the press. Asexplained in connection with the first form of the invention, theoperator will activate the control switch to cause the piston-cylindermotor 140, acting through finger 157 to rotate the pickup blade assembly131 to cause the working edge 154 of the pickup blade 144 to come intocontact with lithographic plate 124, thus to pick up the foreignparticles from the plate onto the blade, or to dislodge these particlesin such a manner that they will be picked up by subsequent rollers andcarried from roller to roller away from the plate cylinder.

When the operator has accomplished his result in clearing thelithographic plate, he releases the control thick walled cylindricaltube 137 insures that there will be no sag in the working edge 154 ofthe pickup blade 144 between the ball bearings 145,145.

Should the pickup blade become worn, it can either be replaced asexplained in connection with the first form of the invention, or theproper alignment of it with respect to the surface of the lithographicplate 124 can be re-established by use of the threaded positioning rods151,151.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

1. For use with a lithographic printing press capable of producingprinted work having a press frame and a rotating plate cylinder forsupporting a lithographic plate, apparatus for removing foreignparticles from said lithographic plate, which comprises:

A. a pair of mounting arms mounted to and extending from said pressframe at either end of said plate cylinder, each arm defining anelongated slot, a mounting stud slidably mounted within each slot, andmeans including a positioning rod mounted in each rod mounting arm andoperable on the one of said studs in said mounting arm to positivelyposition said stud, to thereby independently adjust the position of saidstuds in said slots;

B. a thick-walled rigid cylindrical tube mounted on said mounting studsand pivotally movable about an axis parallel to the axis of rotation ofsaid plate cylinder and spaced therefrom, said rigid cylindrical tubeextending substantially the entire length of said plate cylinder;

C. a pickup blade having a working edge portion fixedly mounted to saidrigid cylindrical tube to position said working edge portion thereof inparallel relation to the axis of rotation of said plate cylinder, and

D. a piston-cylinder motor operably connected between said tube and saidmain frame and operable from a position overlooking the printed workoutput from the press causing said rigid tube to be rotated from a firstposition wherein the working edge portion of said pickup blade will bein longitudinal contact with said lithographic plate over substantiallythe entire length thereof and a second position wherein said pickupblade will be in spaced relation to said plate.

2. The apparatus of claim 1 wherein said pickup blade is slidablymounted with respect to said rigid cylindrical tube.

3. The apparatus of claim 1 wherein said pickup blade is made of aplastic material.

4. The apparatus of claim 3 wherein said pickup blade is made of plasticmaterial selected from the group consisting of polyethylene,polytetrafluorethylene and neoprene.

5. The apparatus of claim 2 wherein said pickup blade is made of aplastic material.

6. The apparatus of claim 5 wherein said pickup blade is made of plasticmaterial selected from the group consisting of polyethylene,polytetrafluorethylene and neoprene.

1. For use with a lithographic printing press capable of producingprinted work having a press frame and a rotating plate cylinder forsupporting a lithographic plate, apparatus for removing foreignparticles from said lithographic plate, which comprises: A. a pair ofmounting arms mounted to and extending from said press frame at eitherend of said plate cylinder, each arm defining an elongated slot, amounting stud slidably mounted within each slot, and means including apositioning rod mounted in each rod mounting arm and operable on the oneof said studs in said mounting arm to positively position said stud, tothereby independently adjust the position of said studs in said slots;B. a thick-walled rigid cylindrical tube mounted on said mounting studsand pivotally movable about an axis parallel to the axis of rotation ofsaid plate cylinder and spaced therefrom, said rigid cylindrical tubeextending substantially the entire length of said plate cylinder; C. apickup blade having a working edge portion fixedly mounted to said rigidcylindrical tube to position said working edge portion thereof inparallel relation to the axis of rotation of said plate cylinder, and D.a piston-cylinder motor operably connected between said tube and saidmain frame and operable from a position overlooking the printed workoutput from the press causing said rigid tube to be rotated from a firstposition wherein the working edge portion of said pickup blade will bein longitudinal contact with said lithographic plate over substantiallythe entire length thereof and a second position wherein said pickupblade will be in spaced relation to said plate.
 2. The apparatus ofclaim 1 wherein said pickup blade is slidably mounted with respect tosaid rigid cylindrical tube.
 3. The apparatus of claim 1 wherein saidpickup blade is made of a plastic material.
 4. The apparatus of claim 3wherein said pickup blade is made of plastic material selected from thegroup consisting of polyethylene, polytetrafluorethylene and neoprene.5. The apparatus of claim 2 wherein said pickup blade is made of aplastic material.
 6. The apparatus of claim 5 wherein said pickup bladeis made of plastic material selected from the group consisTing ofpolyethylene, polytetrafluorethylene and neoprene.